[R 통계분석] 단일표본 t검정

[R 통계분석] 단일표본 t검정

#1. 방법

t.test(x, y = NULL,
       alternative = c("two.sided", "less", "greater"),
       mu = 모집단 평균, paired = FALSE, var.equal = FALSE,
       conf.level = 0.95, ...)

▶ x에 데이터 입력, y는 입력하지 않음.
▶ mu=모집단평균 옵션 입력 시 단일표본 t검정 수

#2. 예제

> 코드

#데이터 생성
set.seed(1)
height=rnorm(50,175,5)
population_mean=177

#t검정 수행
#귀무가설 : height = population_mean
t.test(height,mu=population_mean)

#귀무가설 : height < population_mean
t.test(height,mu=population_mean, alternative="greater")

#귀무가설 : height > population_mean
t.test(height,mu=population_mean, alternative="less")

> 실행결과

> t.test(height,mu=population_mean)

    One Sample t-test

data:  height
t = -2.5477, df = 49, p-value = 0.01403
alternative hypothesis: true mean is not equal to 177
95 percent confidence interval:
 174.3208 176.6836
sample estimates:
mean of x
 175.5022

> t.test(height,mu=population_mean, alternative="greater")

    One Sample t-test

data:  height
t = -2.5477, df = 49, p-value = 0.993
alternative hypothesis: true mean is greater than 177
95 percent confidence interval:
 174.5166      Inf
sample estimates:
mean of x
 175.5022

> t.test(height,mu=population_mean, alternative="less")

    One Sample t-test

data:  height
t = -2.5477, df = 49, p-value = 0.007015
alternative hypothesis: true mean is less than 177
95 percent confidence interval:
     -Inf 176.4879
sample estimates:
mean of x
 175.5022